1. Field of the Invention
The present invention relates to a non-destructive inspection apparatus or method for inspecting drugs and food-products. More particularly, the present invention relates to a radiation inspection apparatus and a radiation inspection method suitable for inspecting occurrences of a stockout of a packaged object, whose inside cannot be observed with visual light owing to packaging materials.
2. Description of the Related Art
Hitherto, an inspection apparatus using visual or infrared light has been known as an apparatus for inspecting occurrences of a stockout of a packaged food-product. This inspection apparatus using visual light or infrared light usually irradiates an object to be inspected with visual or infrared light and then receives light reflected or transmitted by the object by using a CCD camera. Thus, the inspection apparatus obtains image information concerning the inside of a package and determines the number of objects included in the package according to the shape thereof.
Meanwhile, in recent years, many kinds of aluminum foil and boxes, which are disabled to transmit light, have been employed as the manners of packaging food-products and drugs. Such inspection apparatuses using light are no use to inspect an occurrence of a stockout of the object packaged in such a manner.
Moreover, the inspection apparatus using light has a problem that, even if a packaging material constituted by a light-transmissive material is used, a result of inspection is significantly affected by the coloring of the surface of the packaging material.
It is sufficient for seeing the inner situation of the package wrapped by the packaging material made of a non-transmissive material therethrough to use an inspection apparatus using radiation, such as X-rays. In a conventional radiation inspection apparatus, radiation transmitted through the object to be inspected is detected by a one-dimensional or two-dimensional radiation detector. Then, a pattern of a perspective two-dimensional image of the object contained in the package is recognized by performing image processing using pixel information. Thus, the conventional apparatus determines whether or not a stockout of the object included in the package occurs according to the pattern thereof. Therefore, the conventional apparatus has problems that large-scale image processing should be performed so as to realize a high-speed inline system, and that both the hardware and software of the apparatus are too costly.
The invention is accomplished in view of such circumstances. Accordingly, an object of the invention is to provide a radiation inspection apparatus and a radiation inspection method that does not need large-scale image processing, which is needed by the conventional apparatus, and that is enabled to use the hardware and software for image processing, which are relatively simple, and to determine with a low-cost configuration whether or not a stockout of an object packaged by a non-transmissive material occurs. As used herein, the term xe2x80x9cstockoutxe2x80x9d is meant to indicate either the condition wherein one or more objects are missing from the package or wherein one or more inferior or defective objects are included in the package.
To achieve the foregoing object, according to the invention, there is provided a radiation inspection apparatus, which comprises a radiation generator for generating radiation toward an object to be inspected; a radiation detector, disposed in such a way to face the radiation generator, for detecting the radiation transmitted through the object to be inspected and outputting a pixel gray level information for each pixel consisting an image of the object to be inspected; and a data processor unit for performing data processing by using the pixel gray level information outputted from the radiation detector. In this apparatus, the data processor unit totalizes the number of pixels, whose gray levels represented by the pixel gray level information, which is outputted from the radiation detector, are within a predetermined gray level range, and determines from a totalization of the number of pixels whether or not a stockout of the object to be inspected occurs.
The invention achieves the desired purpose by employing simple data processing, that is, totalizing the number of pixels, whose pixel gray levels are within the predetermined gray level range, and determining from a result of the totalization of the number of pixels whether or not a stockout of the object occurs, instead of performing pattern recognition of a perspective image by image processing using pixel information outputted from the radiation detector.
That is, pixels of a radiation perspective image of the object contained in the package have gray levels, which differ from those of pixels of other parts thereof. Thus, such a perspective image can be visually checked. Therefore, the gray levels of pixels of the object of a perspective image are included in a gray level range differing from a gray level range that includes the gray levels of pixels of other parts of the image. Such a gray level range can preliminarily be known. Thus, the gray level range is preliminarily set. Further, the number of pixels having gray levels included in the set gray level range is totalized. Thus, there is a correlation between a result of the totalization of the number of such pixels and the projected area of the object contained in the package. For example, in the case that the objects to be inspected are commodities, which are objects arranged in a certain direction and accommodated in a packaging container, the result of the totalization of the number of pixels is proportional to the number of the objects obtained in the packaging container. Therefore, it can correctly be determined by totalization of the number of pixels, whose gray levels are within the predetermined gray level range, of the radiation perspective image whether or not a stockout of the objects contained in the package occurs.